Traditionally, postage stamps have been manufactured with a water activated adhesive and perforated holes. More recently, the postal services of many countries have converted, at least partially, to a self-adhesive or Pressure Sensitive Adhesive (PSA) construction which does not require any medium for activation and is formed from a laminate in which the self-adhesive postage stamps are releasably adhered to a release liner.
Traditionally self-adhesive stamps utilize die cutting technology proven during the production of billions of PSA unperforated postage stamps. Since 1990, virtually all known commercially-available self-adhesive stamps are die cut around the periphery to provide shape and enhance removal of individual stamps from the release liner. The largest user of self-adhesive stamps worldwide is the United States Postal Service. Originally, their PSA stamps were die cut in straight lines. As such, they were not always recognized by collectors as xe2x80x9cstampsxe2x80x9d since an important feature for collectors xe2x80x9cstampsxe2x80x9d is the full hole perforation and the ability of a user to separate individual stamps from each other with the liner intact. Therefore, more recently, the die cut technology was modified to include a sinusoidal pattern so as to create simulated perforations; and even more recently, stamps have been issued with only the liner microperforated to make severing one stamp from another easier.
These developments in self-adhesive die cut stamps have been designed to create self-adhesive stamps which are well accepted by both the public, the collector and even the postal service itself. The public favors self-adhesive stamps, due to its convenience in use, and collectors find them attractive to collect. However, until self-adhesives acquired simulated perforations, self-adhesive stamps were sometimes rejected by mail carriers as not being stamps (because they didn""t look like stamps).
Accordingly, a need exists for a self-adhesive stamp product that can meet the user""s need for convenience and which still has the traditional stamp-like appearance before and after use in mail.
In accordance with the present invention, a postage stamp product is provided comprising a laminate of a sheet of stamp paper containing stamp graphics on one side and a self-adhesive layer on the other side, and wherein said sheet is releasably adhered to a release liner.
The self-adhesive layer is preferably formed of a pressure sensitive adhesive which is adapted to provide clean perforations using male/female punch tooling. The release level of the adhesive precludes separation of the stamp paper during processing while providing convenient stamp removal from the release liner immediately prior to consumer use.
The laminate is perforated with a series of holes to form an array of stamps, including liner, connected to one another by unperforated portions. Preferably, the laminate is die cut through the release liner, around each stamp, to provide easy removal of the liner from each stamp.
Furthermore, in accordance with the invention, a method and apparatus for manufacturing the aforesaid stamp product is provided as follows.
One or more sheets of self-adhesive unperforated stamp stock laminate are disposed between a perforator comprising an array of upper pins and appropriately disposed lower hollow cutting members. The pins are reciprocally translated through the stock and into a longitudinal bore in the cutting member to perforate the stamp laminate. The length of the pins in relation to the thickness of the laminate and the depth of the longitudinal base is sufficient to perforate the laminate cleanly without carrying the perforation core waste back onto the perforator or laminate.